Most mufflers employ various types of baffles in order to diffuse the sound by sending the sound in many different non-cohesive directions. Many other mufflers use packing materials in order to absorb the sound within the packing material. Both of these methods accomplish noise reduction by absorbing sound energy or redirecting the sound energy to cause interference that results in an equalization of sound pressure highs and lows.
The problem with baffles and packing materials is that the baffles and packing materials tend to impede the flow of exhaust from an internal combustion engine thus causing back pressure to be applied to the engine. The more back pressure exerting on the engine, the less efficient the engine performs. Accordingly, performance mufflers are currently available which have lower back pressure thus enabling better engine performance. However, the performance mufflers are often considerably louder than mufflers employing baffles and packing materials.
In an attempt to obtain a muffler with both low back pressure and noise levels, electronic mufflers have come to the forefront. Besides being more expensive than non-electronic mufflers to manufacture, the electrical systems of the electronic mufflers have proven to be unreliable due to the harsh environment in which mufflers operate.
Accordingly, a need exists for an economical method and apparatus of reducing noise in an exhaust stream while causing very low back pressure and achieving adequate noise levels.